Substitution of breast feeding by the untimely introduction of other foodstuffs, usually of low or inadequate nutritional value, contributes to poor and unhealthy feeding practices and malnutrition. Particularly in the poor communities of the world, lack of sanitation, clean water, refrigeration, sterilizing equipment, fuel and time for boiling water, of money for adequate quantities of milkpowder, or education to read instructions, can contribute to make bottle-feeding a baby killer. Especially in warm countries, milk-powders can be over-diluted (and often are because of their expense) with unclean water in an unsterilized feeding-bottle which is then often left to stand in the heat. The result is that babies who are bottle-fed are many times more likely than breastfed babies both to be malnourished and to contract infections, setting up the cycle of malnutrition and infection at an even earlier and more vulnerable age than most susceptible children.
It is argued that poor mothers buy expensive milk powders because there is a kind of status attached to buying powdered milks. The advertisements for breast-milk substitute formulas used to show happy, health babies, so mothers think if they feed them to their babies they will be happy and healthy. The arrival in the 1980s of follow-up milks for older babies (6 months) allowed manufacturers to dodge some of the advertising restrictions imposed on breast-milk substitutes. However this has added another set of problems. For mothers who cannot read, follow-on milks in smaller cans may be given to smaller (new-born) babies. The higher protein content in follow-on milks can cause kidney damage in a younger baby. Weaning foods, such as processed baby rice, may be sold where rice is the staple, at 20 or 30 times the price and carry the same risk of infection as milks.
Breast-feeding during the first 4-6 months of life protects the baby against diabetes, pneumonia, ear infections, polio and other illnesses, and it reduces the mother's risk of breast and ovarian cancers. Fewer breast-fed babies die of cot death (sudden infant death syndrome.)
During the 1970s, large numbers of women in the developing world abandoned breastfeeding for the use of powdered formulas. Studies published in 1983 confirmed that breast-feeding still predominates in the rural areas of almost all developing countries, but that in the growing metropolitan areas bottle-feeding is on the rise. Estimated global sales of infant formulas rose from US$ 1.5 billion in 1978 to US$ 4 billion in 1983. Most of the increase in formula sales occurred in the more rapidly industrializing developing countries. Data available in 1987 indicated a continuing decline is breast-feeding, in both incidence and duration, in developing countries, especially in urban areas. The substitution is frequently encouraged by commercial interests using misleading advertising. Thirty percent of the revenue of Bangladesh television comes from baby food advertisements.
UNICEF claims that 1.5 million babies die per year because they are not breast-fed. In poor countries babies are up to 25 times more likely to die if they are not breast-fed. Separate studies in India and Canada have found that artificially fed infants were three times more likely to contract diarrhoeal infections and twice as likely to suffer from respiratory infections (the two main causes of child death) as infants who were breastfed. In Chile, artificially fed infants have been found to be two or three times more likely to die in the first year of life. In the USA, a study in New York State has found that bottle-fed infants were hospitalized three times more frequently than breastfed infants during their first year of life. In the UK, a bottle-fed baby is 10 times more likely to suffer gastrointestinal illness than a breast-fed one. In a hospital in the Philippines, the decision to encourage breastfeeding instead of bottle-feeding of new-born babies reduced clinical infections by 88%, diarrhoeal infections by 93% and infant mortality by 95% In rural Jamaica, it was found that diarrhoea incidence increased directly with the degree of bottle-feeding, and was three times as high among exclusively bottle-fed compared with exclusively breast-fed infants. In Congo, a UNICEF-sponsored study echoed the evidence accumulating from all over the world that infant malnutrition is frequently co-related with a reduced period of breast-feeding, and warned that the social changes that bring this about are far more complex than is sometimes implied by the 'breast versus bottle' protagonists. A doctor in Dacca said that 60-70% of the severely malnourished infants he treats have been bottle-fed.